Q&A: A Forum for Green Building Experts and Beginners

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I have a home that is approx 800 sq ft in size not counting the attic.
I'd like to spray foam it.
It is about 70 years old built with 2x4's.
Crawl space, no bsmt.
A little over 8' walls on main floor ( 100")
I was planning on doing 3" of closed cell 2LB spray foam from a professional.
Also, as well in the rafters since it is a sloped roof but I'd like the attic finished since it is 7ft high, I would have some nice, temp regulated storage and I am planning to install the furnace there too.

It is clear that an HRV is not for providing "make-up" air, but do any suppliers sell the HRV unit with/out motors so that spot specific venting that I'm planing to direct-vent to the outdoors can be ran through an HRV box with the make-up air coming in to temper that cold air?

Would anyone know of a company that locates the source of humidity in the home? I have been having so much trouble getting Sears to replace the water heater they installed at the end of last year. They keep demanding statements from inspectors to prove that the humidity in my guest house is actually being caused by the water heater! There was no humidity beforehand. Now there is condensation build-up on the windows, which drips down and causes mold to grow on the window sills.

Per a phone call 4/15/15 from Fibertec, they have expressed concerns that my original posting unfairly places them in a negative light. To avoid the potential option of Fibertec taking legal action for perceived damages, I am temporarily removing this post so that I can discuss Fibertec's concerns with them and substantiate my claims in greater detail for their awareness. Once completed (shortly) I will repost my thread with any potential corrections.

We are building a super insulated house. I've been a carpenter long enough and studied enough that I'm confidant the envelope will be tight.

The thing I am least comfortable designing is the ventilation system. I am planning a balanced, ducted system, with the HRV acting as the air handler. Simple enough to balance if the system includes only fresh and exhaust air, but what about bath and laundry area fans? Do you run those through the HRV as well?

And what about the kitchen range vent? If these DON'T run through the HRV, where does their make up air come from? Passive vents?

In 1998, we purchased a house in NY right on the border between climate zone 5 and 6. It was dark.... I mean, really really dark inside and out. The house was 1.5 stories and about 1500sqft with a large room in the front with a high cathedral ceiling. Limited windows, large 2-car garage taking up the southwest corner.

I am getting into the details of our radiant and DHW design and was looking for some feedback on the boiler choice. I have been planning on using a combi boiler and so far favored a Bosch model, but have started to wonder whether the Bosch would short cycle in my planned setup.

Is it possible to have too many return Air vents in house? Of course I guess anything is possible.
But I believe it was someone on this site, that responded to an issue I have with a Lennar home.. IT was build as part of their "green' series. I lived in the house for 9 months and after my second trip to the emergency room due to air quality or lack there of in the house... I moved out... And I have been trying for 2 years to fix it.